Single thread locking stitch



Dec. 14, 1954 L.. KlRscH SINGLE THREAD LOCKING STITCH Filed Aug. 13, 1951 IN VEN TOR LOU/S KQSGH RNE United States Patent O SINGLE THREAD LOCKING STITCH Louis Kirsch, New York, N. Y.

Application August 13, 1951, Serial No. 241,527

3 Claims. (Cl. 112-262) The present invention relates to a lock stitch which is formed from a single thread.

Lock stitches have heretofore been proposed but such stitches have been interlinked with each other to prevent them from unraveling or being pulled apart. To sew such lock stitches of the prior art, the sewing machines used for forming them have included bobbins or spools containing the lower thread.

The present invention therefore contemplates the provision of a lock stitch that is formed from only a single thread which single thread is so intertwined or interlinked in the stitching that application of tension at any loose or severed portion of the thread will cause an adjacent stitch to lock so that the thread can not unravel and be pulled out from the material to which it has been sewed.

The present invention contemplates the provision of a stitch construction such that each stitch is individually locked so that should the thread break at any point, it cannot be pulled out or the material which has been sewn together by it, separated, thereby providing a lockdstitch that is superior to those heretofore propose Heretofore, bobbin made stitches have been used to sew seams together but should the thread thereof break, the seam will open, since each stitch thereof is not individually locked. In distinction, should the thread break in a stitch of the present invention which has` been applied to sew together a seam, it (the seam) will not open since the stitches are individually locked.

Since the present invention contemplates the provision of a lock stitch formed from a single thread, the sewing machine that is used will have no bobbin and may therefore be used with a relatively heavy thread of any size, which heretofore has not been possible since machines employing bobbins must be limited to relatively light threads.

By the provision of the single thread lock stitch of the present invention, where otherwise it would be desired to use a lock stitch of the prior art employing at least two threads, there is eliminated in machines which have many needles, the requirement of an equal number (for the additional thread) of tension devices and bobbins, spools of yarn, etc., thereby reducing the size and complexity of the apparatus required.

In the past, sewing machines which require a bobbin generally when used with heavy threads, are extremely large, of comparatively great weight and are limited in the size of thread since the size of the bobbins are limited. However, since with the single thread lock stitch of the present invention, bobbins, bobbin winders, spools of yarn and tensioners, are eliminated from the sewing apparatus, it is comparatively small and of light weight.

These bobbin machines require frequent replenishing of the bobbins thereby increasing the cost of labor and causing such sewing machine to be repeatedly idle. On the other hand, the sewing machine forming the lock stitch of the present invention eliminates these disadvantages of bobbin machines and yet provides a mechanically superior stitch reducing most considerably the set-up time and bobbin replenishing time and results in a machine which comparatively is not idle.

In these bobbin machines, which are continuously operated, requiring replacement of the bobbins, breaks in the stitch will occur requiring repair to the slipped or skipped stitches. Such repair is also required when a ICC machine is stopped for the replacement of an empty bobbin. On the other hand, with sewing machlnes forming the lock stitch of the present invention, such repair to the stitches is unnecessary and the flow of work sewed thereby will be continuous.

The present invention further may be applied to an existing chain stitch machine to convert it into one by which a lock stitch may be sewed without the addition of bobbins or extra threads for each needle of the machine.

My invention also will have great application to shlrring machines which have a multiplicity of needles since it makes unnecessary the requirement of a large quantity of additional spools of thread and tensioners to lock the stitch, thereby increasing the quantity of work, rate of production and reduction in required size of multiple needle shirring machine equipment.

These, other and further objects, advantages and uses of the present invention will be clear from the description which follows and the drawings appended thereto, in which Fig. l is a plan view of a lock stitch formed from a single thread according to my invention.

Fig. 2 is a section on the line 2-2 of Fig. 1, showing the stitch locked in both directions.

Fig. 3 is a similar sectional view with the stitch opened to show its construction.

Fig. 4 is a bottom plan view of Fig. l.

Fig. 5 is a section on the line 5-5 of Fig. 2.

Fig. 6 is a section on the line 6-6 of Fig. 2.

Referring now to Figs. 1 to 6 inclusive, I have illustrated a lock stitch embodying my invention which is formed from the single thread 10 and by which the fabrics 12 and 14 are sewed together.

In the description herein, a complete stitch as viewed above the upper textile or fabric 12, shall be considered as formed by the thread between the point 16 at which it enters the upper textile or fabric 12 to form the rst stitch 18 and the point 20 at which it enters the upper textile or fabric 12 to form the succeeding stitch 22.

As viewed below the under textile or fabric 14, a complete stitch shall be considered as formed by the thread 10 between the loop 24 of the preceding stitch 26 at the point of entry 16 and the loop 28 of the first stitch 18 at the point of entry 20 to form the succeeding stitch 22.

As will be more fully described on the underside of the textiles or fabrics which are sewn together by my single thread lock stitch, the thread 10 is formed into the integral knot 30 which is located between the loop 24 of the preceding stitch 26 and the loop 28 of the first stitch 18.

Thus, every lock stitch according to my invention includes on the underside of the textile fabric, where it is not ordinarily visible, a knot, by means of which the stitches are individually locked, and, as will be seen, prevented from unraveling. The lock stitches appear above the textile or fabric, similar to a standard stitch.

For an understanding of my description, it shall be understood that the portion of the thread which goes through the loop of a preceding stitch is to the left of the figures (Figs. l to 4) and the portion of the thread that continues into the succeeding stitch through the loop of the stitch itself is on the right of these gures.

The needle of the sewing machine (not shown) by means of which my novel lock stitch may be sewed, pierces the textile or fabrics 12 and 14 and carries the yarn or thread 10 with it, through the loop of the preceding stitch to underneath the textile or fabric.

lt (the yarn or thread 10) through the operation of a sewing mechanism, which is described and claimed in my co-pending application, then continues into the coil or node 34 (see Fig. 3) of the knot 30 (see Fig. 2) to pass into and form the loop 28 of the stitch 18.

From there, the yarn or thread 10 returns to complete the formation of the coil or node 34 continuing back and then drawn by the needle of the sewing machine through theflobop 24 of the preceding stitch 26 to above the textile or a ric.

The material is fed by the feed dog and the needley again enters the textile or fabric at the second point of entry 2t) to complete the stitch ISr thereabove and "through" is locked in both directions, as is illustrateddwithjparl' ticularity iny Fig.j 2,

With the lockstitch,hereproposed, referringto Fig, 2, should the thread of' the stitch above the textile or fabric be broken and tension applied to that` portion, 42 of the thread located to the left of and leading t0`the loop 28, asindicated byl the arrow 3l, thenfthe loop 23 will be tightened'around the thread 'going to the' succeeding stitch 22. This',tighteningofl the looplocks the stitch" at that point. l

' Should tensionv be applied, inthe direction, ofthe arrow` 48V to theA portion v i4 ofthe thread or yarn,- leading toaknot, Whiichjr'oif` 'convenience in illustration and description, I, refer-to byl thefreferencehumeral 46- (see Fig. 2`),`upon breaking the thread forming theV stitch above the textile `or yfabrlic,'thenthis knot 46 ywill be .tightened and the stitch willbe lockedtherebecause the' knot cannotbe drawn throughtheloop 50; This looplSt), it will berecognized, is similar or analogous to the yloop 24.

ltwill be notedjrornl thelgures thatallof-the loops, such as 24, 2S, 4i), 50, are small-tovprevent knots, such as 30, 36, 46, 'from being drawn theirethroughl in4 the event of breakagev lof. thethread which would otherwise occur if such loops werelarge enough to permit.the knots tobe drawn therethrough. This feature is best seen in Figurel 2 where itis quite apparent that knot 4 6, for example, -could.,not be drawnthroughthebight of loop 50. In other words, the loops arey close to theA knotsand ldo not extend outwardly therefrom, to permitl these* loops to openv suthciently toV passV a, knot. in the.. event; of--breakage ofa thread. lt willlalsobenoted that should a thread break releasing loop L1 (Figu're) andztension,heap-` plied to the free top.strand,44as indicated-byarrow, 48 (Figure 2), the kn'oti 46. of'. the broken stitchy will be drawn toward loop 50. This causes a slackening and doubling of lowerstrand Swhich, together with knot 46, is too "bulky to pass through4 loop 50'..

Thus, if the stitch breaks above the fabric or textile, it cannotv slip and 'be' unraveled butwill be' locked at" this point Aninspection of Fig. 4 establishes that the threador yarn leads to a knot 391Ianditherefore should the' thread or yarn 'break beneath the lower textile orfabric 14, any tensionapplied to a loose end will result onlyin tightening therknot to which/it' leads.

l"Thus, the elfect below the 'fabric is the same as that abovethe fabric, that is, the stitch cannotslip and unravel 'but will lock at-the'point at which the yarn or threadrnight'break.

It Will now be apparent that I have provided a lock stitch folrnedfrom asin'gl'e 'thread"that cannot unravel or be pulled out of the textiles or fabrics which are sewn together by it and thereby separated should the thread break at any part thereof.

It will be further recognized that I have proposed in each stitch between the loop` thereof and the loop of the preceding stitch the provision of an integral knot formed in the threadcornprising the stitch and which knot individually locks the stitch when tension is applied or transmitted to the knot or loop luy-pulling the fabric apart or pulling the free end of the thread. Thus, there is now provided a lock'stit'ch sewed lfrom a single thread which eliminates the necessity of another" thread and corresponding requirement of a bobbin, bobbin winder, second spool of yarn and tensioner.

While I have shown and described a certain specific example of myinvention, it will be understood that such example is illustrative onlyandy is not given as a limitation, since othermodications Within the spirit and scope ofk theinventionwill bejapparent to those skilled in the art.

' It willvalso kbe understood that the lock stitch suggested herein and having an integral intermediate'knot continuing from spaced loops oneachside'of the knot, the loops and the knotvbeingformed 'fromthes'ame thread, may have otherapplications, for example, in the art 'ofknit- Hence, I do not .intendto limitmyselfthereto, but in-l tend'.to c laimimyinvention, as'broadlyasimay be permitted"by,the, s'tatefof the prior' art and .-'therterms of the appended 'cla'ift'ns-V l. A t singlethread. lockingstitch.comprising a line of lengthsy of single threyadzon thetop sideof thematerial tolbesewn, andta-,series'of in-,linetloops interlocked with succeedingiloops onthe underside of `saidmziteril, each loop, having aknotadjacent its bight'endportion.whereby each Saidf. klQt. iS. prevented. ,from passing'. through said bight portion of each precedingloop.

2'. Theloc;king stitchl as defined-,in andfbyclaim l, whereinthepdimensions of tthe ,openings formed by the bightgfportions, of ,the loops relativekto thesize of the knots ,arej such. so; as `to prevent. the knots ,from passing through thesalid olgvenilllgs.`

3. The locking` stitclras-deined in and by claim.2, wherein ,said threadhas a free end `whenbrokenand when said end-tis pulled ,the `lirstknot thereon ,engages the bight portion ofa'precedingloop, th'e thread adjacentthe knot beingdrawnbackwardto produce adoublingvefect and whichljointly withlsaid knot assistsin locking the stitches.

References `Cited, in. they le l of .this v.patent n UNER-D SWESRATENTS, Number. Name.: Date 1,575,186 Baker l Mar. 2, 1926 

